It is quite common for square-backed vehicles to collect, depending upon the weather and road conditions, undesirable particulate material such as dirt, dust, grim, mud and snow on a rear panel of the vehicle. Such square-backed vehicles generally include such land vehicles as buses, vans, semi-trailers, motor homes, travel trailers and a wide variety of trucks.
The problem is caused by the aerodynamic shape of a square-backed vehicle in which the parallel airstreams passing over the side, roof and bottom panels of the vehicle create a vacuum immediately behind the rear vehicle panel causing turbulent swirling eddy currents that pull the undesirable roadway particulate material upward depositing the particulate material on the rear panel.
The problem is particularly serious and presents a safety hazard when the deposited undesirable particulate material hampers a driver from having clear vision through a window in the rear panel. Furthermore, it is not unusual for the deposited particulate material to cover and obscure rear lights of the vehicle increasing the probability that the vehicle may be involved in a rear end accident.
The problem has been known for many years and a wide variety of solutions have been proposed and implemented. Such solutions include using a wide variety of air deflectors and air foils incorporated in or attached to the rear part of the vehicle for deflecting one or more of the parallel airstreams inward along the rear panel. Many of such prior deflectors or air foils, although partially effective, were cumbersome and created additional drag that lowers fuel efficiency of the vehicle. Some of the attached deflectors had insufficient strength and were easily deformed and over time broke creating safety hazards. An additional solution that has been proposed has been to attach pyramid or conical shaped projections over the rear panel that extend rearward to minimize the creation of a vacuum at the rear of the square-backed vehicle.
One of the principle objects of this invention is to provide an improved air foil system for attaching to the upper rear edge of a square-backed vehicle that is not only more effective in maintaining the rear panel free from undesirable particulate material but also increases the fuel efficiency of the vehicle.
These and other objects and advantages of this invention will become apparent upon reading a detailed description of a preferred embodiment.